Log barkers of the rotatory abrading head type



LOG BARKERS OF THE ROTATORY ABRADING HEAD TYPE Filed Aug. 22, 1955 INVENTOR HARRY A. STEWART ATTORNEY United States LOG BARKERS OF THE ROTATORY ABRADING HEAD TYPE Harry A. Stewart, Vancouver, British Columbia, Canada Application August 22, 1955, Serial No. 529,733

2 Claims. (Cl. 144208) mounted abrading heads which are adapted to be heldagainst a log by centrifugal force, and to provide means for driving the heads whereby a projection on the log could be passed with a minimum amount of shock being transmitted to the machine and the area immediately surrounding the projection could be cleanly stripped of its bark.

Referring to the accompanying drawings:

Figure 1 is a plan view of the invention.

Figure 2 is an enlarged vertical sectional view taken on the line 22 of Figure 1.

Figure 3 is a fragmentary horizontal section through an abrading head and a bight portion of its mounting yoke, as indicated by the section line 3-3 in Figure 2.

In the drawings like characters of reference indicate corresponding parts in each figure.

The numeral 1 indicates a base plate having a central opening 3 bordered by a vertical flange 4 which is beveled on it stop surface to form a track 5. Rotatably mounted upon the base plate is an annular rotor 7 which is channel shaped in cross section and has a bottom flange 8, a top flange 9, and a connecting web it). Depending from the bottom flange 8 are circumferentially spaced brackets 12 each journaling a tapered roller 14 which rides upon the track of the base plate.

An electric motor 16 is mounted upon the base plate 1 and has its drive shaft 17 coupled as at 18 to a shaft 19. The shaft 19 is journaled in a bearing 21 and is fitted at its free end with a beveled pinion 22;. A crown gear 24 is secured to the outer periphery of the web it) of the rotor 7 and is engaged by the pinion to drive said rotor in the direction shown by the arrow in Figure l.

Spaced 120 degrees about the circumference of the rotor are C-shaped yokes 26, each having a short top arm 27, an elongated bottom arm 28 and a vertical arm 29. A tubular pivot bolt 30 extends through the top flange 9 of the rotor and through the arm 27 and a pivot bolt 31 extends through the flange 8 and the arm 28 so that the yoke is mounted for oscillation within the rotor and adjacent its inner periphery. Mounted upon the arm 28 of each yoke is an electric motor 34 having a drive shaft 35 and aligned with said shaft is a housing 36 which is supported by the vertical arm 29. The housing 36 journals a horizontal shaft 37 which is coupled as at 38 to the drive shaft 35 and the housing is provided with a fork member 39 which journals two vertically aligned atent Q shafts 41. The shafts 37 and 41 are operatively connected by a suitable difierential gear train generally indicated by the numeral 43 and adapted to permit one of the shafts 41 to rotate at a speed different from the speed of the other when required. Fixed to the upper and lower shafts 41 of each housing 36 so as to rotate therewith are upper and lower cylindrical sleeves 45 and 46 respectively, which together form an abrading head 47. The upper end 49 of the sleeve 45 is conical in form for reasons that will hereinafter appear. The outer periphery of the head 47 is provided with suitable abrading elements 50 which are here shown as being short spikes projecting outwardly from said head. It is intended that some provision be made for resiliently or otherwise mounting the abrading elements so that there is a certain amount of give to said elements, thus lessening the danger of breakage when engaging the log.

The rotor 7 is partially enclosed by a cylindrical dished cover 54 having a bottom flange 55 by which it is bolted or otherwise secured to the base plate 1. A central opening 57 is provided in the cover and adjacent said opening an inner vertical flange 58 is formed to provide a track for cricumferentially spaced rollers 59 mounted upon the top flange 9 of the rotor and adapted to keep said rotor centered upon the base plate. The top of the cover 54 is provided with a series of collector rings 60 which are connected as at 61 to a source of electrical power. A bracket 64 is secured to the top of the rotor above each motor 34 and supports a series of brushes 65 which engage the collector rings. The brushes are connected to an adjacent motor 34 by leads 66 which extend through the bore of the tubular pivot bolt 36.

in the operation of the device it is intended, as indicated by the arrow A in Figure 2, that the logs to be debarked be fed vertically downwards through the barker by a suitable conveyor which would include fed rolls 70. The feed rolls would hold the log against rotation and pass it through the center of the rotor where it could be acted upon by the abrading heads. When the motor 16 is energized to drive the rotor the heads 47 will swing by centrifugal force towards the center of the barker and it will be understood that suitable stops, not shown, would be provided to limit the inward swinging movement of said heads. The motors 34, which serve as counterweights to the abrading assemblies, are energized to rotate the heads at an appropriate speed and the log is lowered into contact therewith. As the leading end of the descending log engages the conical upper ends 49 of the sleeves 45, the heads will be forced apart a sufficient distance to permit the passage of the log and the abrading elements 50 will strip the bark from the log down to the cambium layer of the wood. A projection on the log would first be engaged by the elements on each of the upper sleeves and might tend to retard the rotation of said sleeve but by virtue of the diiferential gear train 43 the lower sleeve could continue to rotate at its normal speed so that no undue strain is imposed upon the motor 34, shock is reduced to a minimum and the stripping action is substantially continuous with no bark being left adhering to the log surface.

What I claim as my invention is:

1. A log barker comprising a horizontally disposed annular rotor through which logs are adapted to be conveyed, a yoke swingingly mounted within said rotor upon a vertical axis disposed intermediate the horizontal extent of said yoke, an abrading head supported upon a bight portion formed by an inner end of said yoke, said head having vertically aligned cylindrical sleeves, a prime mover having a drive shaft and being supported upon an outer end of the yoke, a differential gear train operatively connecting the sleeves and the drive shaft, and means for 3 4 driving the rotor, said prime mover serving as a counter- References Cited in the file of this patent weight means for swinging the head into abrading engage- UNITED STATES PATENTS I j a c 1 ment with a log surface in response to centrifugal torce 2,353,125 Carpman July 11 1944 produced by rotation of the rotor. 2 541767 J F b 1 1 2. A log barker as claimed in claim 1, wherein one of 5 Ones n e 951 the cylindrical sleeves of the abrading head is conical at FOREIGN PATENTS its free end. 147,444 Sweden Oct. 26, 1954 

